Bump slab from 0.4.10 to 0.4.11 in /client

Bumps [slab](https://github.com/tokio-rs/slab) from 0.4.10 to 0.4.11.
- [Release notes](https://github.com/tokio-rs/slab/releases)
- [Changelog](https://github.com/tokio-rs/slab/blob/master/CHANGELOG.md)
- [Commits](https://github.com/tokio-rs/slab/compare/v0.4.10...v0.4.11)

---
updated-dependencies:
- dependency-name: slab
  dependency-version: 0.4.11
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

client/Cargo.lock

@@ -1079,9 +1079,9 @@ dependencies = [
 
 [[package]]
 name = "slab"
-version = "0.4.10"
+version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "04dc19736151f35336d325007ac991178d504a119863a2fcb3758cdb5e52c50d"
+checksum = "7a2ae44ef20feb57a68b23d846850f861394c2e02dc425a50098ae8c90267589"
 
 [[package]]
 name = "smallvec"